#include <iostream>
#include <string>
#include <vector>
using namespace std;
 
int main()
{
    string str1 = "", str2 = "";
    cin >> str1 >> str2;
    int n1 = str1.size(), n2 = str2.size();
    // if(n1 == 0 || n2 == 0)
    // {
    //     cout << max(n1, n2);
    //     return 0;
    // }
 
    vector<vector<int>> dp(n1 + 1, vector<int>(n2 + 1));
    for(int i = 1; i <= n1; ++i)
    {
        dp[i][0] = i;
    }
    for(int j = 1; j <= n2; ++j)
    {
        dp[0][j] = j;
    }
 
    for(int i = 1; i <= n1; ++i)
    {
        for(int j = 1; j <= n2; ++j)
        {
            if(str1[i - 1] == str2[j - 1])
                dp[i][j] = dp[i - 1][j - 1];
            else
                dp[i][j] = 1 + min(dp[i - 1][j - 1], min(dp[i - 1][j], dp[i][j - 1]));
        }
    }
    cout << dp[n1][n2] << endl;
    return 0;
}